Learn about this topic in these articles:

repair of genetic mutations

...is the repair mechanism for damage caused by ultraviolet radiation. Ultraviolet radiation joins adjacent thymines, creating thymine dimers, which, if not repaired, may cause mutations. Special
repair enzymes either cut the bond between the thymines or excise the bonded dimer and replace it with two single thymines. If both of these repair methods fail, a third method allows the DNA...